This invention relates generally to rotary irrigation sprinklers, and more particularly, to a rotary sprinkler of the impact drive type, intended for use in an environment where the sprinkler is likely to come in contact with adjacent vegetation.
As is well known in the art, when a rotary irrigation sprinkler is employed in an environment where the sprinkler is likely to come in contact with adjacent vegetation, such as when employed for irrigating an ivy ground cover or the like, the vegetation will frequently become entangled on the sprinkler or otherwise interfere with the normal operation thereof. For example, this interference can take the form of contacting the drive arm of a sprinkler and disrupting its free swinging motion, or becoming entangled with and causing malfunction of the trip mechanism of a part circle sprinkler.
This problem is particularly troublesome where the sprinkler is mounted for pop-up operation. That is, when the sprinkler is arranged to move axially between a downwardly retracted non-operating position and an upwardly extended operating position, adjacent vegetation frequently interferes, not only with the normal operation of the sprinkler in its operating position, but also with the axial movement between its non-operating and operating positions.
Prior art devices have been proposed which provide for partial enclosure of a sprinkler, but none has entirely enclosed all of the sprinkler mechanism. Accordingly, these prior devices include, for example, exposed levers for adjusting part circle operation, which levers can easily become entangled on adjacent vegetation. It will also be appreciated that these levers are readily available for unauthorized tampering, as by vandals.
Another method for dealing with these problems has been to provide a stationary subterranean housing into which a pop-up sprinkler is retracted when not in operation. This type of housing usually includes a cover attached to the top of the sprinkler, which cover closes the housing when the sprinkler is in its retracted position, thereby entirely enclosing the sprinkler.
This subterranean housing functions satisfactorily for preventing adjacent vegetation from becoming entangled on the sprinkler while the sprinkler is not in use, and the housing also inhibits unauthorized tampering with the sprinkler. However, such a housing does not move with the sprinkler to its upwardly extended operating position, and as a result, the sprinkler is subject to substantial interference from adjacent vegetation when in operation. Further, experience with such housings has shown that, although the cover attached to the sprinkler assists in pushing vegetation aside as the sprinkler moves to its extended position, the same vegetation frequently catches on the exposed sprinkler and is drawn into the housing as the sprinkler is retracted, thereby preventing complete retraction of the sprinkler into the housing.
Accordingly, there has existed a need for a convenient and effective device for preventing interference with the operation of an impact drive irrigation sprinkler by adjacent vegetation. As will become apparent from the following, the present invention satisfies that need.